Ambulocetus
Ambulocetus (meaning "walking whale") is a primitive cetacean that originated from Eocene Pakistan, but has since been brought back from extinction into modern Eurasia and North America. It is named as such because it has short limbs and large feet used for swimming, it also swims by undulating its back vertically.. Along with other members of Ambulocetidae, it is a transitional animal species that seems to shows how whales evolved from land-living mammals. While some species of Ambulocetus alive today are semi-aquatic, most species of Ambulocetus are fully aquatic. Most species tolerate freshwater, brackish fish, and saltwater, but one species, Darwin's Ambulocetus (including a live Ambulocetus that was used in BBC's Walking with Prehistoric Beasts), is freshwater only. All known Ambulocetus lacks external ears, its skull has a long snout and eyes facing sideways (they face upwards in pakicetids), locate high on the skull like in hippos (the closest relatives of whales). Several features shared with other basal cetaceans indicate the close affinities of Ambulocetus with these animals; it has an adaptation in the nose that enables it to swallow underwater, and its periotic bone's structure is like those of more advanced whales, enabling it to hear well underwater. In addition, its teeth are similar to those of other primitive cetaceans. Ambulocetus has a feeding morphology similar to that of crocodiles: a long snout, pointed teeth, and strong jaw adductor muscles. Like crocodilians, depending on a species, Ambulocetus killed its prey either by holding it in its jaw and either drowning it or thrashing it with violent motions. Similar to larger crocodilians, adult Ambulocetus are ambush predators that feed on larger fish, aquatic tetrapods and, in some species, terrestrial animals near the water. In contrast to crocodilians, it has the ability to chew its prey but does minimal food processing with its teeth. The short forelimbs of Ambulocetus has five fingers on each hand and its long hindlimbs has four toes on each foot. It has dense osteosclerotic limb bones, so it is well-adapted for living in water but moved slowly, hunting as an ambush predator. Its pelvis is attached to its spine, like land mammals and unlike most whales. Its powerful tail, which lacks a tail fluke, is used for locomotion, and it moves similar to a native modern river otter. Pakicetids and ambulocetids use their large feet and hind limbs for propulsion; morphologically, the thigh and leg of Ambulocetus are shortened, but the feet stayed large; this resulted in a reduction in lever arm but a retention of a large propulsive surface, allowing its hind limb to function as an oar. In its later Eocene cetacean relatives, such as the basilosaurids and remingtonocetids, the tail gained a fluke and became the dominating source of propulsion, while the leg became more reduced and rudimentary. Ambulocetus ranges from about the size of a harbor seal to about the size of a male sea lion, much larger than Pakicetus. Category:Species Category:Animals Category:Non-Sapient Species Category:Real Life Species Category:Mammals Category:Mammalian Species Category:Revived Category:Whales Category:Whales And Relatives Category:Carnivores